In 1869 Douw made her first visit to China on behalf of the Woman's Union Missionary Society of America for Heathen Lands (WUMS).
[Note 1] She went to Beijing with two other women, Mrs Catherine Bonney and Miss Emily Adams, to open a boarding school for girls.
They played an important role, working with women in situations where the presence of male missionaries would be inappropriate or forbidden.
She set up a fund with the Woman’s Union Missionary Society of America for evangelistic work in Shanghai called the Douw Foundation.
They were eventually rescued by a combined international force of troops and she returned to America, but never fully recovered from this experience and died in 1911.